This invention relates in general to a lens measuring instrument and deals more particularly with an improved instrument for determining the box dimensions of a spectacle lens or the like and for measuring segments or determining other critical lens dimensions.
Spectacle lenses are provided in a variety of shapes and for convenience in fitting such lenses a boxing method has been adopted wherein the various dimensions of a lens are related to the horizontal and vertical dimensions of a rectangle circumscribing the lens, as is well known in the art. It is generally essential that these dimensions be accurately determined to enable selection of a properly sized lens and to measure or locate the position of segments and other major points or lines of reference thereon essential to the proper finishing of the lens.
Accordingly, it is the general aim of the present invention to provide an improved measuring instrument for determining the box dimensions of a lens and for measuring the position of segments or other critical points or lines of reference on a lens.